Metal and Metalloid Contaminants in Atmospheric Aerosols from Mining Operations

Mining operations, including crushing, grinding, smelting, refining, and tailings management, are a significant source of airborne metal and metalloid contaminants such as As, Pb, Cd and other potentially toxic elements. Dust particles emitted from mining operations can accumulate in surrounding soils, natural waters and vegetation at relatively high concentrations through wind and water transport. Human exposure to the dust can occur through inhalation and, especially in the case of children, incidental dust ingestion, particularly during the early years when children are likely to exhibit pica. Furthermore, smelting operations release metals and metalloids in the form of fumes and ultra-fine particulate matter, which disperses more readily than coarser soil dusts. Of specific concern, these fine particulates can be transported to the lungs, allowing contaminants to be transferred into the blood stream. The main aim of this research is to assess the role of atmospheric aerosol and dust in the transport of metal and metalloid contaminants from mining operations to assess the deleterious impacts of these emissions to ecology and human health. In a field campaign, ambient particulates from five mining sites and four reference sites were examined utilizing micro-orifice deposit impactors (MOUDI), total suspended particulate (TSP) collectors, a scanning mobility particle sizer (SMPS), and Dusttrak optical particle counters for an understanding of the fate and transport of atmospheric aerosols. One of the major findings from size-resolved chemical characterization at three mining sites showed that the majority of the contaminant concentrations were found in the fine size fraction (<1 micrometer). Further, metal and metalloids (e.g. As, Cd, and Pb) around smelting activities are significantly enriched in both the coarse and fine size fraction when compared to reference sites. Additionally, with dust events being a growing concern because of predicted climate change and mine tailings being a significant source for dust, high wind conditions around mine tailings were studied for dust generation. Relative humidity was found to play an important predicting role in atmospheric dust concentration. More generally, findings indicate mining activities remain a serious threat to human health and ecology despite the regulations in place to protect from their pollution

Licenced to pollute but not to poison : the ineffectiveness of regulatory authorities at protecting public health from atmospheric arsenic, lead and other contaminants resulting from mining and smelting operations

This article details and examines the impact of significant inconsistencies in pollution licencing, monitoring and reporting from Australia's leading mining and smelting communities of Mount Isa in Queensland and Port Pirie in South Australia. Although emissions to the environment are regulated according to Australia's national air quality standards, significant atmospheric point source toxic emissions of arsenic, lead and sulfur dioxide continue to contaminate Mount Isa and Port Pirie communities. Short-term atmospheric contaminant emissions across residential areas from the Mount Isa Mines operations are significant: in 2011, 24-h maximum suspended particulate (TSP) values for lead-in-air and arsenic-in-air were 12.8μg/m³ and 2973ng/m³, respectively. The relevant Queensland air quality objectives for lead and arsenic are 0.5μg/m³ (TSP) and 6ng/m³ (PM₁₀), respectively, averaged over a year. Mount Isa is also blanketed by elevated sulfur dioxide concentrations, with the Australian and Queensland 1-h air quality standard (0.2ppm) being exceeded on 27 occasions in 2011. At Port Pirie, contamination of the urban environment is arguably worse with 24-h maximum TSP values for lead-in-air and arsenic-in-air of 22.57μg/m³ (2011) and 250ng/m³ (2009), respectively. Port Pirie has an annual average lead-in-air standard of 0.5μg/m³ (TSP) but there are no set values for arsenic. In 2012, the national 1-h standard for sulfur dioxide was exceeded 50 times in Port Pirie. Despite chronic childhood blood lead exposures in both communities, there is a history of denial and downplaying of the source and impact of the contamination. A contributory factor to this pattern of behaviour is the fragmented and inconsistent delivery of data as well as its interpretation in relation to environmental and health impacts from exposures. This study reviews available data sources and makes inference to the impacts from contamination and in doing so, explains why the current regulatory framework fails to protect the impacted communities.18 page(s